In my comment I wrote just three sentences. The middle sentence starts off "Even the original M1 MacBook Air..." Then the link I provided is to an investigation on charging speeds of the MacBook Air.
Apple supplies a 30W charger in the box, so I think it's fair to say that a third-party 30W charger is "full speed" (in the sense of "as good as the stock one", if not full speed in all potential scenarios GP might or might not care about).
When iPhones shipped with chargers they were only 5w despite being able to charge from faster chargers.